Yeah, why isn't this thread smoking hot? Nearly everyone's submitted to a little lit at one point or another, but my guess is very few submitters are actually readers.
I personally subscribe to AGNI and Gettysburg Review. The GR, by the way, is having a 25th anniversary sale--12 bucks for a year plus a t-shirt, and other tantalizing offers.
Frankly, mags like The New Yorker and Atlantic (each usually offering one story, sometimes none at all) don't count. Plus they don't need your money, but many other publications do. The folks at AGNI are a bunch of volunteers working in a basement somewhere on the Boston U campus. Your subscription pays to keep the machine going, not make a profit. I don't know if this factors into your decision, but it factored into mine when deciding where to send my bread. Artists should support the arts, I feel. Slicker mags seem like another beast, though they may have art inside them from time to time.
(Just took a peek at the One Story web page. I'm sold. Thanks, Bubaste.)